We've been using T1's for years and never changed the connection to a faster Cable Modem. I am concerned about support, return to service. I cannot find in legalese Cable vs T1's FCC Regulations SLA's.
I'm very interested in what the current regulations are for returning T1 and Cable service to a business. I've not had too many issues with my T1's and when I have they've jumped on the issue immediately and stayed with it until resolved.
If I get a high speed cable modem for my business and it fails I'm wondering how I'm protected by the FCC for return to service.
A cable modem will typically have higher downstream and upstream bandwidth than a T1, however you should be aware of the two major differences (one of which you've already mentioned):
T1 lines typically come with a very strong service level agreement (SLA), and T1 providers take these very seriously (largely due to the T1's heritage as a telecommunications service).
Cable providers typically don't offer the same kind of uptime/availability guarantees, nor do their SLAs typically have the same kind of stiff penalties as T- or DS loops.
T1 bandwidth is symmetrical, dedicated and guaranteed end-to end. Your T1 will push 1.5Mbit/sec from your router to the far end.
Cable bandwidth is asymmetrical (typically you get a fatter download pipe), shared (multiple modems to a node, sharing the RF channels), and typically not guaranteed in your contract -- the speeds are "Up to __Mbit/sec".
While cable companies are usually on top of quality of service/speed issues they can ignore you to a greater degree than your T1 provider could.
Add one more that Jason Berg mentioned in re: SLAs:
Most cable SLAs (at least in my area - NY Metro) don't even mention these things, so even though our providers are good about responding to those issues they aren't strictly obligated to.
I don't believe you're protected by the FCC if your T1 goes down anyway. Those carriers are covered by what your state's utilities division has regulated, along with the terms of the contract of what you bought. Read the fine print on your current contract. Contact your cable vendor and ask what they have for service, SLA, and ask for the fine print that backs up what they tell you.
@Dennis makes a good point as well, although these days most cable ISPs have an upload far superior to the T1 even if its nonsymmetrical.
Can not be answered. It totally (!) depends on your contract. Even with T1 it totally depends on your contract.
THe main problem may be getting cable modem for businesses WITH a SLA.
A good combbo may be having both, and use the T1 for fallback. That said, where I am a T11 is primitive ancient like hell - you can get a SDSL with up to 8mbit in BOTH direction for quite some cheap money WITH BUSINESS SLA.